1. Field of the Invention
The present invention relates generally to a device for sensing cartridge replacement time in items of image forming equipment such as a printer or facsimile using an inkjet injecting apparatus, and, more particularly, to a process and device in which the quantity of ink within a cartridge that stores ink for performing a printing operation is sensed so as to ascertain the replacement time of the cartridge.
2. Description of Related Art
Typically, ink cartridges of a printer are replaced by separating an ink cartridge from a head part for injecting ink. Such systems use wholly replaceable and integrally-provided ink cartridges and head parts that fit such cartridges. Among the exemplars of the contemporary practice is Hunt (U.S. Pat. No. 5,434,603, Ink Cartridge With Passageway For Ink Level Indicator, Jul. 18, 1995) discussing an ink jet pen supply cartridge having a spring biased ink reservoir with a visual indication of remaining ink quantity. Durst et al. (U.S. Pat. No. 5,406,320, Ink Replacement Assemblies For Ink Jet Printer, Apr. 11, 1995) discusses an ink supply housing of an ink replenishment system including a pair of opposed side walls having a plurality of attachments spaced in respective opposing vertical columns and detachable detents coupled at one of the attachments. Shimoda (U.S. Pat. No. 5,552,815, Ink Jet Apparatus Including Means For Regulating An Amount Of Ink And An Amount Of Air In An Ink Tank Relative To Each Other, Sep. 3, 1996) discusses an ink jet apparatus having a head for forming an image picture on a recording paper, a subsidiary ink tank detachably coupled to the head for accommodating ink and air therein, and a cartridge on which the head and the subsidiary ink tank are mounted and used for scanning the recording region. Dunn et al. (U.S. Pat. No. 4,931,812, Flow Control System For Ink Cartridges, Jun. 5, 1990) discusses an ink cartridge system which includes a reservoir maintained at a negative pressure in communication with a printing system. MacLane et al. (U.S. Pat. No. 5,184,147, Ink Jet Print Head Maintenance System, Feb. 2, 1993) discusses an ink jet print head cleaning and maintenance system using a specialized baffle diverting ink that enters the purge chamber and discusses a vent port through in which the vacuum is drawn. From my study of the contemporary practice and the art, I find that there is a need for an effective device for sensing cartridge replacement time in a printer equipment using an inkjet injecting apparatus such as an inkjet printer or facsimile, especially those using a floating mechanism.